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HONOR AGREEMENT
Subject: ME3322-A/QUP Midterm #2
I ______________________________(Print your name) understand and accept my
responsibility as a member of the Georgia Tech community to uphold the Honor Code at all
times. I affirm that I have not received any unauthorized help on this exam and that all
work is my own. I agree in my honor that I will keep the exam materials confidential
without telling anybody about it until 10:00 AM on Wednesday, July 9, 2025.
Signature: _______________________ Date: ___________________
For QUP students, you should have already printed out this page.
Please sign your name and use it as your cover page. Otherwise, if
you forgot to print it out, please write a few words on a blank
sheet and sign it in lieu of the form.
Name: ____________________________ Page | 1 of 4
ME 3322A/QUP Thermodynamics – Summer 2025
Midterm #2
In-person: 12:30-2:10 pm, Tuesday, July 8
QUP-section: Use Honorlock between 10:00 am (July 8) and 2:00 am (July 9).
Closed book. You will need a calculator and may bring with you the 4-page equation sheets plus
2-page crib sheets of your own. Your notes can be handwritten, copied or typed, and you can also write
or highlight on the equation sheets but you cannot resize them. Cell phones, laptops, and other
electronics are not permitted for in-person exam and permitted only for the stated purposes during the
online proctoring exam. You do not need to follow the methodology steps. However, partial credit
may be given to those who show the derivations but end up with wrong numerical results. In general,
no questions will be answered during the exam, please figure it out to the best you can and write down
any doubts or unusual assumptions/comments.
Problem 1. Short Questions (60 points total).
(i) (15 pts) Multiple choice questions. Answer either True or False.
Statements True or False
(a) For a closed system that changes from state 1 to state 2 in an
internally reversible process, the amount of heat transferred into
2
the system can be calculated by Q12 = TdS , where T and S are
1
the absolute temperature and entropy of the system.
(b) For an isolated system, its energy remains constant, and its
entropy cannot decrease.
(c) The absolute temperature is defined based on the triple point of
water, whose temperature is 273.15 K and pressure is 1 atm.
(d) Three examples of irreversible processes are: (1) passing a current
through an electrical resistor; (2) heat transfer across a wall with a
finite temperature difference; (3) piston motion with friction.
(e) A Carnot cycle is composed of two constant-pressure processes
and two isothermal processes.
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(ii) (15 pts) A well-insulated cylinder is divided into two equal parts (A and B) with a
wall in between that allows heat transfer between the two sides, as shown. Initially, the
temperatures and other properties are given in the following figure. After a while, a thermal
equilibrium is reached between A and B. Use R = 0.287 kJ/kg·K, cv = 0.718 kJ/kg·K, and
c p = 1.005 kJ/kg·K to determine the following
(a) (8 pts) The final equilibrium temperature, Tf .
(b) (7 pts) The entropy generation in this process, .
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(iii) (15 pts) Air at a flow rate of m = 0.53 kg/s through a horizontal diffuser at steady
state, as shown in the figure. Assume the process is internally reversible and adiabatic, find
(a) (7 pts) the exit temperature T2 and (b) (8 pts) pressure p2. Given R = 0.287 kJ/kg·K, cv =
0.718 kJ/kg·K, and c p = 1.005 kJ/kg·K.
(iv) (15 pts) An adiabatic steam turbine
operates at a steady state with a mass flow rate m =
2.3 kg/s. The inlet is at p1 = 8.0 MPa and T1 = 600C,
and the exit pressure is p2 = 0.06 bar with a quality
x2 = 0.95. The needed data are provided. Make
suitable assumptions to determine the following
quantities.
(a) The power produced by the turbine.
(b) The entropy generation rate of the turbine.
(c) The isentropic efficiency of the turbine.
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Problem 2 (40 pts). In a carbon dioxide sequestration plant, as shown in the figure, a CO2
gas with a mass flow rate m = 12 kg/s enters the first-stage compressor at p1 = 0.1 MPa and
T1 = 25°C. Compressor 1 may be modeled as adiabatic and reversible. The CO2 gas exits the
compressor at p2 = 3 MPa. It is then cooled in Heat Exchanger 1 to T3 = 35°C by transferring
heat to the ambient environment (air) at T0 = 25C. The pressure drop in the pipeline may be
neglected, that is, p3 = p2 . The CO2 gas at states 1, 2, and 3 may be modeled as an ideal gas
with a constant specific heat (given c p = 0.915 kJ/kg K and R = 0.189 kJ/kg K ).
A second-stage compressor raises the pressure and temperature of the CO 2 to p4 = 7
MPa and T4 = 130°C, respectively. Compressor 2 is adiabatic, but its isentropic efficiency is
less than 100%. The CO2 exits the second compressor and is cooled in Heat Exchanger 2 by
the ambient air until it becomes saturated liquid at p5 = p4 . Properties of CO2 are given in the
following table (blanks are meant for you to determine their values). Do not use any Tables
or Data not provided in the problem.
State # T (C) p (bar) h (kJ/kg) s (kJ/kg·K) Note
1 25 1 505.9 2.740 Ideal gas
2 30 Ideal gas
3 35 30 Ideal gas
4 130 70 563.0 2.135 Superheated vapor
5 28.7 (sat) 70 294.6 1.312 Saturated liquid
(a) (8 pts) Find the missing properties of state 2. Then, determine the power required
for Compressor 1.
(b) (6 pts) Find h3 and s3 . Then determine the entropy generation rate in Compressor 2.
(c) (6 pts) Sketch all the processes and states in a T−s diagram. Note that the critical
properties of CO2 are Tc = 31°C and Pc = 7.38 MPa.
(d) (10 pts) Determine the heat transfer rate to the ambient environment in each heat
exchanger.
(e) (10 pts) Evaluate the entropy generation rate of each heat exchanger. Assume that
the boundary temperature is the same as the ambient temperature: Tb = T0 = 25C .
